Genetically engineered mice and rats are widely used as models for defining the molecular mechanisms underlying cancer etiology and for evaluating new strategies for cancer treatment and prevention. The Genome Editing and Animal Models Shared Resource (GEAM), formerly the Transgenic and Mutant Animal Facility, has served as a shared resource for the University of Wisconsin Carbone Cancer Center (UWCCC) for over two decades and is one of the elite facilities within the United States in offering a comprehensive array of services related to generation and preservation of genome-edited animal models. The primary mission of the GEAM is to make state-of-the-art genome editing technologies accessible to UWCCC members. Specific Aim 1 is to provide the expertise and infrastructure required to generate novel and relevant genome-edited or transgenic animal models and genome-edited cell models for use in cancer research. GEAM staff are capable of serving UWCCC members in all aspects of experiment planning and execution, including design of efficient and specific approaches to achieve the desired loss, gain, or alteration of gene function using CRISPR/Cas9 or other genome editing and transgene-based approaches; design, production and use of the required genome editing reagents or transgene vectors; identification of animals that carry the desired genome edit or transgene; and minimization of off target edits. Our skills in reproductive biology, embryo manipulation, and animal husbandry enable us to edit the genomes of inbred mouse and rat strains that exhibit low reproductive capacity. Specific Aim 2 is to provide state-of-the-art services that allow valuable animal models to be banked and recovered as needed to preserve these animal models or reduce the costs associated with maintaining live breeding stock for novel models that are not actively being studied. GEAM staff are highly experienced and capable of cryopreserving mouse and rat embryos or sperm and recovering mouse and rat models through embryo transfer or in vitro fertilization. In addition, we are capable of rederiving mouse and rat strains to eliminate pathogens that may compromise research or prevent animal models from being imported into our vivaria or shared between investigators working at different institutions. Since its inception, GEAM has generated hundreds of transgenic, knockout, and genome-edited mouse and rat models for UWCCC members. Sixty-one unique UWCCC members have been served during the current CCSG funding cycle, an increase of 30% compared to the previous grant cycle. Support from the CCSG allows our services to be provided to UWCCC members at costs far below those of commercial vendors or similar cores at other research universities. Convenient access to our first rate, cost-effective services enhances the ability of UWCCC investigators to conduct innovative research that advances the UWCCC strategic mission.